Compounding dynamo-electric machines.



No. 7i6,345.

E. B; RAYMOND.

Patented Dec. I6, |902.

COMPOUNDING DYNAMO ELECTRIC MACHINES.

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No. 716,345. Patented Dec. I6, i902.

E. B. RAYMOND.

CMPOUNDING DYNAMO ELECTRIC MACHINES.

(Application filed Apr. 26. 1902.) f N o M o d el.)

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UNITED STATES PATENT OFFICE.

EDWARD B. RAYMOND, OF SCHENECTADY, NEIV YORK, ASSIGNOR TO GEN-I ERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

COMPOUNDING DYNAMO-ELECTRIC MACHINES.

SPECIFICATION forming' part 0f Letters Patent N0. 716,345, datedDecember 16, 1902.

Original application led October 3l, 1896, Serial No. 610,680. Dividedand this application filed April 26, 1902. Serial No.104,872. (Nomodel.)

To @ZZ whom t may concern.-

Be it known that I, EDWARD B. RAYMOND, a citizen of the United States,residing' at Schenectady, county ot Schenectady, State of 5 New York,have invented certain new and useful Improvements in CompoundingDynamo-Electric Machines, (Case No. 2,832, division ofmy priorapplication, Serial No. 610,680, filed October 31, 1896,) of which thefollowing ro is a specification.

My invention relates to methods of compounding dynamo-electric machines,and is particularly applicable to those of the altermating-.currenttype. It dispenses with the I5 use of a commutator and seriesfield-winding and avoids the sparking necessarily involved in thecommutation of the line-current or any part thereof.

It is well known that as the load on a gen- 2o erator increases theresistance drop in the armature and in the line increases, which causesthe translating devices to receive a lower voltage. Itis also a factthat a similar effect is produced in an alternating-current system by anincrease in the lag of the current. The

principal reasons for this latter eiect I understand to be, first, thatthe lagging current tends to demagnetize the generator field-magnets;second, that the resultant electromotive force supplied to thetranslating devices is diminished by the counter electromotive force ofself-induction, and, third, that the inductive drop in the armature andin the feeders is greater with a lagging current.

It is possible by the use of my invention to regulate the machine towhich my improvements are applied in such a way as to compensate bothfor any change in the quantity of the armature-current and also for anyin- 4o crease or decrease in the lag of the current in the system. It isalso possible to adj ust either for what is known as straightcompounding or for any desired percentage of overcompounding, so thatthe voltage either at the terminals of the machine or at any selectedpoint in the system may be kept constant whatever may be the load or thelag.

Myimprovements are also applicable to circuits regulated byfeeder-regulators or like 5o devices separate from the generator and toany other use 1n which the conditions of the circuit are to becontrolled in accordance with the voltage, current, or lag.

To these ends my invention consists in a new method of generating acurrent whose volume or voltage depends upon the conditions of thecircuit to be controlled and a new mechanical regulating deviceresponsive to the changes in such current, as will be hereinafter morefully described and claimed.

I have illustrated certain embodiments of my invention in theaccompanying drawings, in which- Figure l is a plan, and Fig. 2 a sideelevation, of my improved regulator in its preferred form. Figs. 3 and 4are respectively a perspective and a cross-section of a portion of thesame. Figs. 5 and 6 are diagrams illustrating the relations of thevarious currents and electromotive forces in the system under 7odifferent conditions. Fig. 7 is a diagrammatic illustration of theconnections of my improved compounding apparatus applied to theregulation of an alternating-current dynamo-electric machine. Fig. 8 isadiagram 75 of a similar arrangement for adjusting a feeder-regulator,and Fig. 9 shows my improved regulator applied to straight compounding.

In Figs. l and 2, A is a rheostatz or other 8o controller. Bis asolenoid, and C is the core of the solenoid.

D, Figs. l, 2, 3, and 4, is a rack-bar connected with the arm of therheostat, as shown. This rack-bar is notched to form a ratchet to engagewith the pawls G G', which are reciprocated by an eccentric G2, drivenby a shaft and pulley K, connected to any suitable motor device, thelatter not being illustrated. By the rotation of the pulley K theeccentric G2 9o is caused to move the pawls G G backward and forwardalong the notches of the bar D. The core C is attached to the leverE4,con nected to one of the pawls G', which is connected to the otherpawl G throughan adjusting device G5. The weight otthis core iscounterbalanced by the weight F upon an eX- tension of the lever. Thearm E' of the lever is connected to a spring E2, the other endof thespring being secured toan adjusting deroo vice E3, carried upon thefixed portion I of the apparatus. A detent H is provided with a suitableclip H', so that by its rotation around the shaft h the pawls G G may beremoved from engagement with the rack. When the current in the solenoidB weakens, the core C is drawn upward by the action of the spring E2,the pawl G is brought into engagement with the bar D, and the switch-armof the rheostat is actuated to cut out the resistance. When the currentin the solenoid B strengthens, the reverse action takes place.

In Fig. 7 I have shown at L an alternatingcurrent dynamo-machine excitedby the direct-current generator M. In series with the ield magneticwindings L of the alternator and with the armature of the exciter, or inany other relation in which a change of resistance will affect thevoltage of the main machine, is placed the current-controller orrheostat A, controlled by the solenoid B, as above described. Thesolenoid B is supplied with current from the secondariesn n of the twotransformers N and N. In the form shown the two secondaries areconnected in series. The transformer N has its primary in series withthe armature-circuit of the main machine and is shunted by theresistance R, connected to the points ab. This resistance should,preferably, be entirely non-ind uctive. The transformer N has itsprimary in shunt to the mains. A non-inductive resistance S may beinserted in the circuit of the solenoid B. As will appear below, thearmature-current of the alternator divides between the primary of N andthe resistance R, and the amount of this resistance determines theamount of the compounding and its relation to the inductive andnon-inductive load. The more resistance is included in this circuit thegreater eect is obtained on non-inductive loads and the less oninductive loads. The action of the devices shown in this figure may beunderstood by reference to Figs. 5 and 6, which are diagrams of theelectromotive forces and currents in the system. In Fig. 5 the vector 12 represents in magnitude and phase the electromotive force impressedupon the system by the armature of the main lnachine, and 1 3 representsthe current, lagging by the angle d. The current in the primary of theshunt-transformer may be represented by 1 4., lagging behind theelectromotive force by a nearly-constant angle. The amount of this lagmay be fixed in any given case by properly proportioning the resistanceand self-induction of the windings. The secondary electromotive force ofthis transformer will be nearly in opposition to the electromotive forceimpressed upon the system and may therefore be represented by 1 5. Thissecondary electromotive force will be nearly constant in phase, but willtend to fall slightly in magnitude as the load comeson and as theself-induction of the external circuit increases in machines which arenot provided with regulating devices; but when my improved regulator isused and adjusted for overcompounding it will rather tend to rise. Thecurrent 1 3 in flowing through the series transformer and through 'theresistance R will divide into two components 1 6 and 1 7, nearly atright angles to each other. 1 6 represents the current in the primary ofthe series transformer, lagging behind 1 3, and 1 7 the current in theresistance R, leading 1 3. It will be seen that the resistance R acts asa phase-shifting device. The electromotive force across the primary ofthe series transformer will be seen to be nearly in phase with 1 7,owing to the fact that the resistance R is non-inductive. The secondaryelectromotive force of the series transformer will be nearly inopposition to its primary electromotive force and may be represented by1 8. The two electromotive forces 1 5 and 1 8 are in series, butreversely connected, as will be seen by examination of the connectionsin Fig. 7-that is to say, the primaries of the two transformers are soconnected that when the upper terminal of N receives positive currentfrom the right-hand main the upper terminal of N receives negativecurrent from the same main, and vice Versa. We therefore reverse 1 8 inthe diagram and have 1 9 and 1 5 as the two electromotive forces actingto produce current in the regulator. At no load the electromotive force1 5 of secondary n acts alone. If a non-inductive load comes on thesystem, the electromotive force 1 9 of the secondaryn will be added tothe electromotive force 1 5, and the current in the solenoid B will bedue to the resultant 1 10, which within a certain range of load growssmaller as the current in the series transformer rises. It will be seenthat this result is due to the fact that the angle 9 1-5 is greater thana right angle. It is obvious that the transformers should be so designedthat the range of load within which the resultant 1 10 grows smaller as1 9 rises is well within the range of load for which the generator isdesigned. If the load becomes inductive, the condition of things will beas shown in Fig. 6. The angle 0 has now increased and the vectors 1 6, 17, 1 8, and 1 9 are correspondingly displaced. The result is that 1 9has come more nearly in opposition with 1 5 and the resultant 1 10 isdecreased in magnitude. It will be seen that the action is to decreasethe current in the solenoid as the load or lag upon the circuitincreases. This decrease in the current in the solenoid will cause anincrease in the field excitation of the main generator, as above setforth, and the device will act to maintain constant electromotive forceat any desired point upon the line, according to the design of theapparatus and the value of the non-inductive resistance R.

In Fig. 8 the arrangement is very similar in principle; but in this casemy improvements are applied to regulate the electromotive force of afeeder by varying the amount and sign of its boosting. The rheostat R isreplaced by a feeder-regulator FR,

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which may be ofthe form shown in the patent to Steinmetz, No. 548,400,dated October 22,

1895, or of any other approved form. Then primary of the seriestransformer, still shunted by the resistance R, is connected in serieswith the circuit, as shown, and as the load or lag on the feederincreases the current in the solenoid B decreases, as above explained,with the result that the electromotive force in the feeder is varied tomaintain constant voltage at any selected point on the system whatevermay be the conditions of the circuit.

The form shown in Fig. 9 is similar to that of Fig. 7, but with theseries transformer and its connections omitted. It will be seen that asthe terminal voltage of the generator drops from any cause whatever thecurrent in the solenoid B weakens, which causes the regulator to adj ustthe resistance-box A in such a Way as to strengthen the field of thegenerator.

The arrangements which I have pointed out may be adapted to the purposesof the engineer in ways well understood in the art. When the resistancearound the series coil is changed, as already pointed out, theproportion of compounding or overcompounding with respect to theinductance otn the load is changed, and these effects may be soproportioned that the same compounding effect may be produced Witheither inductive or non-inductive load, or such desired dierence may beobtained as is best suited to the purpose of the installation.

I therefore claim as my invention and desire to secure by Letters'Patent- 1. The method of regulating a main circuit, which consists inapplying to a secondary circuit in series two alternating electromotiveforces, one dependent upon the voltage of the main circuit, and one uponthe current in the main circuit, the two electromotive forces beingdephased by an angle greater than a right angle, and compensating by thevariation of current in said secondary circuit for the variation ofelectromotive force in the main circuit caused by shifting of phase ofcurrent in said circuit.

2. The method of regulating an electric circuit, which consists insupplying to primary windings two alternating electromotive forces, onedepending upon the voltage of the circuit, and one depending upon thecurrent in the circuit, superposing the inductive actions of these twoelectromotive forces or the currents due thereto, on a secondarycircuit, one of said inductive actions being reversed, and through theagency ofthe current in said secondary circuit maintaining asubstantially constant voltage at some point on said electric circuit.

3. The method of regulating an electric circuit, which consists insupplying to primary windings two alternating electromotive forces, onedepending upon the voltage of the circuit, and one depending upon thecurrent in the circuit, and causing the differential action of theseelectromotive forces to actu ate a regulating device, and therebymaintaining a substantially constant voltage at some point on saidelectric circuit.

In Witness whereof I have hereunto set my hand this 25th day of April,1902.

EDWARD B. RAYMOND.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

